标题： 动态拓扑变化、紧化和弦早期宇宙中的波 显示英文标题

标题： Dynamical Topology Change, Compactification and Waves in a Stringy Early Universe

摘要： 精确的字符串解被提出，其中模场随时间变化。它们提供了空间拓扑发生动态变化的例子。其他一些解给出了宇宙学例子，其中某些维度动态地被紧化或模拟了大爆炸前类型的场景。关于有效理论的有效区域以及如何利用弦论信息在几何和拓扑从低能观点来看未明确定义的区域将它们拼接在一起，得出了一些教训。还介绍了其他时间依赖的解，其中不存在尺度层次结构。这些解的动力学性质有所不同，类似于平面引力波。由E. Kiritsis在第2届宇宙学日，巴黎天文台，1994年6月2日至4日所做的报告。 显示英文摘要

摘要： Exact string solutions are presented, where moduli fields are varying with time. They provide examples where a dynamical change of the topology of space is occurring. Some other solutions give cosmological examples where some dimensions are compactified dynamically or simulate pre-big bang type scenarios. Some lessons are drawn concerning the region of validity of effective theories and how they can be glued together, using stringy information in the region where the geometry and topology are not well defined from the low energy point of view. Other time dependent solutions are presented where a hierarchy of scales is absent. Such solutions have dynamics which is qualitatively different and resemble plane gravitational waves. Talk presented by E. Kiritsis in the 2\`eme Journ\'ee Cosmologie, Observatoire de Paris, 2-4 June 1994.